WASHINGTON, D.C. – Sen. Bernie Sanders has promised to build a coalition broad enough to bring nothing less than a political revolution. Elections across the country on Super Tuesday showed where he's falling short.

For all his early success in the Democratic primary, including his California victory on Tuesday, Sanders is struggling to expand his support beyond his core base. AP VoteCast surveys show he's failing to bring in African Americans, women, suburbanites, older and college-educated voters in numbers he'd need to secure the nomination. And for all his plans to draw new Democrats to the polls, there were few signs Tuesday that his movement is behind increases in turnout.

“It is not easy," Sanders said Wednesday, as he acknowledged he wasn't drawing enough of his core coalition voters — young people, Latinos, liberals — to the polls. “What we are trying to do is unprecedented. We are talking about a political revolution.”

Sanders' loss in Texas, a fast-growing and diverse state he hoped to win, demonstrated some of the biggest challenges. The 78-year-old senator won about two-thirds of voters under 30 there and he beat former Vice President Joe Biden with voters under 45 altogether, according to AP VoteCast. But that only takes you so far when a majority of voters are 45 and older.

Sanders also beat Biden handily with Texas' Latinos, nearly one-third of the vote, but Biden maintained his even bigger edge with African Americans and drew about evenly with Sanders among whites. Meanwhile, Sanders showed no particular strength in the state's sprawling suburbs and watched Biden edge him out with women.

The age gap could be problematic in upcoming primaries that increasingly look like must-wins for Sanders. He needs to draw more older voters to his side, while also bringing out his younger supporters at even higher levels than before.

“Several of the big states in the Midwest coming up — Missouri, Michigan, Illinois, Ohio — they tend to be older states,” said William Frey, a demographer and senior fellow at the Brookings Institution. “The issue with Bernie’s coalition is they’re iffy with turnout.”

The demographic setbacks have been bruising for Sanders. His campaign has spent months trying to improve his standing with key groups, such as African Americans, mindful that those voters contributed to his loss to Hillary Clinton in 2016. But Sanders has seen only middling progress. In some states, he's managed to give Biden a challenge with younger blacks, but not enough of those voters are casting ballots to make a difference.

Sanders' solution to this coalition math problem has been to try to bring more of his voters to the game. But Tuesday's elections in Virginia and North Carolina showed little evidence that's happening. There were obvious signs of the sort of enthusiasm Sanders often discusses — new voters drawn to the process by a sense of urgency and a desire to change Washington. In Virginia, a full 500,000 more voters cast ballots Tuesday compared with the 2016 Democratic primary.

But the increased turnout isn't helping Sanders. His vote share dropped from 35% in 2016 to under 25% — and his raw vote total rose by fewer than 50,000 votes. Biden alone earned about 200,000 more votes than Clinton did four years ago.

In North Carolina, Democratic turnout was up by 180,000 votes from 2016. Sanders walked away with 100,000 fewer votes in 2020.

Sanders' base in these states — and across the country — has been remarkably consistent. In addition to young people and Latinos, Sanders garnered support from people who felt left behind financially. He tends to pull in support from men, people without college degrees and liberals.

In some places, this coalition has been able to yield a victory. He banked victories in Nevada, Colorado and California, all states with sizable Latino populations. In California, where about 30% of Democratic primary voters were Latino, VoteCast showed about half of them went to Sanders. In Colorado, where 13% of Democratic voters were Latino, he won a solid 42% of their votes.

But Super Tuesday showed some enduring weaknesses with three other groups of Democratic voters: women, suburbanites and college graduates.

Women make up a decisive majority of Democrats and any potential nominee will likely need to win their vote. But Sanders has struggled to best his rivals with women. In Texas, women slightly favored Biden over Sanders. In Virginia, Biden beat out Sanders among women by more than 2 to 1.

Nor does Sanders have a steady foothold in the suburbs, where the bulk of likely voters in November happen to live. He fared reasonably well in the suburbs of California, Colorado and Texas. But his support was minimal in most other states. He won just 27% of suburbanites in Minnesota, compared with 41% who went for Biden.

He has also faced difficulty in attracting college graduates, a group that is increasingly drawn to the Democratic Party during Donald Trump's presidency. This vulnerability was clear by the crushing defeat in Virginia. College graduates made up more than half of that state's primary voters. He only managed to win 21% of them. About half went with Biden.

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AP VoteCast is a survey of the American electorate conducted by NORC at the University of Chicago for The Associated Press and Fox News. The surveys were conducted for seven days, concluding as polls closed.

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